Multi-Colored Shaped Body

ABSTRACT

The present invention relates to a multi-colored shaped body having layers arranged on top of one another for producing dental restorations, a process for its production and its use for the manufacture of dental restorations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/819,412, filed Jun. 27, 2007, which claims priority pursuant to 35U.S.C. §119, to European Patent Application No. 06120608.2 filed Sep.13, 2006, all of which are incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a multi-colored shaped body having layersarranged on top of one another, which is suitable for manufacturingdental restorations and in which the change of color between theindividual layers cannot be perceived without technical aids.

BACKGROUND OF THE INVENTION

In the discussion that follows, reference is made to certain structuresand/or methods. However, the following references should not beconstrued as an admission that these structures and/or methodsconstitute prior art. Applicant expressly reserves the right todemonstrate that such structures and/or methods do not qualify as priorart.

Dental restoration parts can be manufactured from ceramic or plasticshaped bodies. This procedure is usually mechanical, for example,computer-aided according to a CAD/CAM method. With regard to the finaluse of the dental restoration parts, the shaped bodies should alreadyhave certain aesthetic properties.

Natural teeth are not one-colored, but have a complex coloration.Different areas of the same tooth can differ from each other in colorand transparency. In general, teeth exhibit a color and transparencygradient from transparent in the occlusal area to yellowish-opaque inthe cervical area.

In order to achieve a desired coloration, dental restoration parts whichhave a single color can be subsequently veneered. However, suchveneering usually has to be carried out manually, which istime-consuming. Multi-colored shaped bodies are therefore preferred fromwhich dental restoration parts can be manufactured that satisfyaesthetic requirements without veneering and which have a colorationthat comes as close as possible to natural teeth in terms of color andtransparency, as well as color gradient.

Multi-colored shaped bodies which are built up from several differentlycolored layers are known from the state of the art.

Thus, VITA Zahnfabrik GmbH offers VITABLOCS® Triluxe, which consist ofthree differently colored layers of a feldspar ceramic and are intendedto simplify the manufacture of optically attractive dental restorationparts. These restoration parts are, however, still veneered.

U.S. Pat. No. 5,151,044 describes multi-layered blocks made from plasticmaterials which can be used for the manufacture of artificial teeth ordenture parts. These blocks preferably contain up to three differentlycolored layers in order to simulate the color gradient of natural teeth.

Furthermore, it is known from DE 199 44 130 A1 to use blocks comprisingseveral differently colored layers with standardized optical propertiesfor the manufacture of denture parts by means of CAD/CAM methods. Indoing so, the virtual positioning of the restoration part within a blockis optimized such that the color gradient of what later becomes therestoration part comes as close as possible to a corresponding naturaltooth of the patient. Veneering of the restoration parts produced inthis way is said to be dispensable.

However, in the case of the multi-colored shaped bodies which are builtup of differently colored layers, the color boundaries between theindividual layers are clearly perceptible. Therefore the restorationparts produced according to the state of the art must be veneered aspreviously mentioned in order to achieve a restoration satisfying highaesthetic requirements.

DE 197 14 178 A1 describes a process for manufacturing a multi-coloredshaped body wherein the color boundaries between the individual layersare said not to be perceptible. According to this, the contact surfacesof the individual layers are subjected to pressure and the differentlycolored starting materials are brought into intimate contact in theboundary area to allow for a mixing of the starting materials.

However, practice has shown that this process does not lead to anadequate mixing and therefore the boundaries between the colored layersin the thus-produced shaped bodies and restoration parts remainperceptible to the naked eye.

There is therefore a need for a multi-colored shaped body for producingdental restorations with differently colored layers in which no colorboundaries can be seen with the naked eye between the individual layers.

SUMMARY OF THE INVENTION

The invention optionally addresses one or more of the above-mentionedshortcomings associated with the state of the art.

According to one aspect, the present invention provides a multicoloredshaped body having layers arranged on top of one another comprising: atleast two successive and differently colored main layers; and at leasttwo differently colored intermediate layers between the at least twosuccessive and differently colored main layers; wherein a change incolor between these intermediate layers takes place in a direction whichis contrary to the direction of the change in color between the mainlayers.

According to another aspect, the present invention provides amulticolored shaped body having layers arranged on top of one anothercomprising: at least two successive and differently colored main layers;and an intermediate layer between at least two successive anddifferently colored main layers; wherein the intermediate layercomprises a mixture of the materials of the two successive main layers.

According to a further aspect, the present invention provides dentalarticles and processes related to the above-described multi-coloredshaped bodies.

The terms “color” and “colored” within the meaning of the inventionrelate to the color, brightness and translucency of a material, body orlayer. According to the invention the terms “color” and “colored” relatein particular to brightness. Changes in color are therefore understoodto include in particular changes in brightness.

“Translucency” is the light-transmitting capacity of a material, body orlayer, i.e., the ratio of transmitted to incident light intensity.

Colors can for example also be characterized by their Lab value or by acolor code common in the dental industry. Examples of such color codesare the Vitapan Classical® and the Vita 3D Master®, both from VITAZahnfabrik H. Rauter GmbH & Co. KG, and Ivoclar Vivadent AG'sChromascop®.

Measurements of layer thicknesses can for example be made oncross-sections from a shaped body taken vertically with respect to thelayering and polished, by recording scaled microscopic images of thesesections with a stereoscope and carrying out length measurements onthese photographs, e.g., with the analySIS Five image-processingsoftware. In particular, layer thickness means the average of severalthicknesses determined for a layer.

DETAILED DESCRIPTION OF THE INVENTION

A multi-colored shaped body according to the invention having layersarranged on top of one another can comprise:

at least two successive and differently colored main layers; andat least two differently colored intermediate layers between at leasttwo successive and differently colored main layers;wherein a change in color between these intermediate layers takes placein a direction which is contrary to the direction of the change in colorbetween the main layers.

The change in colors can essentially be a change in their respectivebrightness. In one embodiment the change of brightness in theintermediate layers takes place in a direction which is contrary to thedirection of the change in brightness between the main layers.

It has surprisingly been shown that shaped bodies formed and structuredaccording to the invention have color boundaries between differentlycolored main layers that are practically imperceptible to the naked eye.

It has also been recognized that the clear perceptibility of the colorboundaries between individual layers in previously known shaped bodiesis enhanced by an optical illusion.

When observing neighboring surfaces differing in color or brightness,so-called lateral inhibition of neighboring receptors in the retinaoccurs in the human eye. Therefore, in the boundary area of twodifferently colored surfaces the dark surface appears darker than inareas more distant from the boundary area, but the bright area appearsbrighter than in areas further away from the boundary area. Thehigher-contrast changes perceived by the human eye are called Machbands. By this effect the contrast at the color boundary is increasedand the perception of the color boundary enhanced. Because of thiseffect, in a series of differently colored layers each of which isone-colored in itself, within the individual layers a color gradient isperceived which is contrary to the gradient of the colors of theindividual layers. These effects are more strongly perceived withbrighter colors than with darker colors.

The described optical effects are contrary to the desired aim of dentalrestorations to achieve a natural color gradient. Thus, the colorgradient of known multi-colored shaped bodies has boundaries between thelayers that are clearly perceptible. The shaped bodies according to theinvention compensate or even over-compensate for these effects by theinsertion of specially developed intermediate layers. A color gradientis achieved thereby in which the boundaries of the differently coloredlayers are no longer perceptible to the naked eye.

The subject of one embodiment of the invention is a multi-colored shapedbody wherein the intermediate layers lying between two successive anddifferently colored main layers alternately have the colors of thesemain layers. A desired color gradient in which the color boundaries arepractically imperceptible can thereby be achieved using relatively fewcolors.

Another embodiment comprises a multi-colored shaped body wherein,between two successive and differently colored main layers, preciselytwo intermediate layers are arranged and each of these intermediatelayers has the color of the main layer which is adjacent to therespective other intermediate layer.

Accordingly, such a shaped body is also preferred which has at

least one element of four layers arranged on top of one another, whereinthe first layer is a first main layer;the second layer is an intermediate layer having the color of a secondmain layer;the third layer is an intermediate layer having the color of the firstmain layer;the fourth layer is the second main layer.

With shaped bodies according to the invention the total number of mainand intermediate layers is at least four, i.e., there are at least twomain layers and at least two intermediate layers. The shaped bodiesaccording to the invention may have 4 to 20, in particular 4 to 10 andmore particularly 4 to 8 main and intermediate layers.

The increase in contrast which occurs at the boundaries of the mainlayers in the absence of intermediate layers is pronounced to a greateror lesser degree, depending on the translucency and brightness of thelayers involved. With shaped bodies with more than two main layers, itis therefore not absolutely necessary to insert intermediate layers atevery boundary between two main layers. Thus a dental restoration whichsatisfies high aesthetic requirements can be manufactured from a shapedbody which can be produced economically.

In an alternative embodiment a shaped body according to the inventionhas eight layers arranged on top of one another, wherein

(a) the first layer is a first main layer;(b) the second layer is a second main layer;(c) the third layer is an intermediate layer having the color of a thirdmain layer;(d) the fourth layer is an intermediate layer having the color of thesecond main layer;(d) the fifth layer is the third main layer;(e) the sixth layer is an intermediate layer having the color of afourth main layer;(f) the seventh layer is an intermediate layer having the color of thethird main layer; and(g) the eighth layer is the fourth main layer.

A shaped body according to the invention may have a height of 10 mm to20 mm, more particularly 14 mm to 16 mm.

The main layers of the shaped body according to the invention may have athickness of more than 0.5 mm, in particular more than 0.5 mm and up to15 mm, more than 0.5 mm and up to 10 mm, and still more particularly 0.7mm to 8 mm.

The intermediate layers of the shaped body according to the inventionmay have a thickness of up to 0.5 mm, in particular 0.01 mm to 0.5 mm,more particularly 0.1 mm to 0.5 mm, and still more particularly 0.2 mmto 0.4 mm.

A shaped body according to the invention can be formed of any materialsuitable for producing shaped bodies for dental restorations. Suchmaterials include ceramics, glass ceramics, plastics, inorganic-organiccomposites or mixtures thereof.

A shaped body, according to one embodiment, contains (a) Si02, (b) Al203and (c) K2O and/or Na2O. A shaped body according to another embodimentis made from Al203 and/or ZrO2 ceramic material.

Differently colored layers can be of the same material which isdifferently colored in each case, or can be formed of differentmaterials.

The layering of the shaped bodies is can be based on the layering of thecolor codes common in the dental industry, such as the VitapanClassical® or the Vita 3D Master®, both from VITA Zahnfabrik H. RauterGmbH & Co. KG, or Ivoclar Vivadent AG's Chromascop®. The tooth models ofthese color codes in each case define only one color, but similar toteeth are built up of layers of different material mixtures and/orcolors and/or translucencies, and are based on the different colors ofhuman teeth. This basic color allocation is preferably also used in theshaped bodies according to the invention, with the result that thedental restorations produced from them correspond very closely to thenatural tooth.

According to a further embodiment of the invention a multi-coloredshaped body for producing dental restorations may comprise

at least two successive and differently colored main layers andan intermediate layer between at least two successive and differentlycolored main layers,wherein the intermediate layer comprises a mixture of the materials ofthe two successive main layers, and may optionally consist thereof.

The main layers of this other shaped body according to the inventionpreferably have a thickness of more than 0.5 mm, in particular more than0.5 mm and up to 15 mm, more than 0.5 mm and up to 10 mm, and still moreparticularly 0.7 mm to 8 mm.

The intermediate layer of this other shaped body according to theinvention may have a thickness of up to 0.5 mm, in particular 0.01 mm to0.5 mm, particularly 0.1 mm to 0.5 mm, and more particularly 0.2 mm to0.4 mm.

Further embodiments of the invention have the properties with respect topreferred numbers of layers, preferred heights of the shaped body andpreferred materials as described above for the other embodiments.

The invention also relates to a process for manufacturing themulticolored shaped bodies according to the invention having layersarranged on top of one an other, in which the main layers andintermediate layers are arranged on top of one another such that ashaped body according to the invention is obtained.

Finally the invention also relates to the use of the multi-coloredshaped bodies according to the invention for the manufacture of dentalrestorations. The manufacture of dental restorations can becomputer-aided, in particular by means of CAD/CAM methods. Preferreddental restorations are artificial teeth, inlays, onlays, bridges andcrowns.

The invention is explained in more detail below with reference to thefollowing illustrative, non-limiting examples.

Example 1 Two Intermediate Layers

For the manufacture of a multi-colored shaped body having differentlycolored layers, the following materials (glass ceramic powders) areused:

SiO2: 60.0-65.0%

Al203: 16.0-20.0%

K2O: 10.0-14.0%

Na2O: 3.5-6.5%

B203: 0-1.0%

BaO: 0-1.5%

CaO: 0.5-2.5

CeO2: 0-1.0%

TiO2: 0-0.5%

F: 0-0.5%

Pigments: 0.2-1.0%

By appropriate pigment addition, the colorings M1 and M2 of the glassceramic material are produced, wherein M1, for example, corresponds tothe dentine color A2 according to Vitapan Classical® and has a highopacity. M2 corresponds to an incisor color and has a lower opacity. Bydifferent mixing of the materials M1 and M2 four differently coloredmaterial compositions A to D result, which are composed as follows:

Material A: 100% M1

Material B: ⅔ M1, ⅓ M2

Material C: ⅓ M1, ⅔ M2

Material D: 100% M2

The individual materials are introduced gradually in a customary form ofa compression mold so that the following series of layers results:

1st layer: 6th layer:2nd layer: 7th layer:3rd layer: 8th layer:4th layer: 9th layer:5th layer: 10th layer:main layer, material Bmaterial A intermediate layer, material Cintermediate intermediate layer, material Blayer, material B main layer, material Cintermediate intermediate layer, material Dlayer, material A intermediate layer, material Cmain layer, main layer, material D

After filling the compression mold with the individual layers the greenbody is produced in known manner by dry pressing, and then a processableshaped body with an overall height of approximately 10 to 15 mm isproduced by debindering and sintering. This shaped body may optionallybe subjected to further processing.

In the resulting shaped body the intermediate layers have a layerthickness of about 0.2 to about 0.4 mm. With this shaped body, and in adental restoration produced from it, the changes between the individuallayers are surprisingly imperceptible to the naked eye.

Example 2 Two Intermediate Layers

For the manufacture of a multi-colored shaped body having fundamentallydifferently colored layers, the following materials (glass ceramicpowders) are used:

SiO₂: 60.0-65.0%

Al₂O₃: 16.0-20.0%

K₂O: 10.0-14.0%

Na₂O: 3.5-6.5%

B₂O₃: 0-1.0%

BaO: 0-1.5%

CaO: 0.5-2.5%

CeO₂: 0-1.0%

TiO₂: 0-0.5%

F: 0-0.5%

Pigments: 0.2-1.0%

By appropriate pigment addition, the colorings M1 and M2 of the glassceramic material are produced, wherein M1, for example, corresponds tothe dentine color A2 according to Vitapan Classical® and has a highopacity. M2 corresponds to an incisor color and has a lower opacity. Bydifferent mixing of the materials M1 and M2 four differently coloredmaterial compositions A to D result, and from these in turn sixdifferently colored materials of the intermediate layers AB1, AB2, BC1,BC2, CD1, CD2:

Material A: 100% M1

Material B: ⅔ M1, ⅓ M2Material C: ⅓ M1, ⅔ M2

Material D: 100% M2

Material AB1: ⅓A, ⅔ BMaterial AB2: ⅔ A, ⅓ BMaterial BC1: ⅓ B, ⅔ CMaterial BC2: ⅔ B, ⅓ CMaterial CD1: ⅓ C, ⅔ DMaterial CD2: ⅔ C, ⅓ D

The individual materials are introduced gradually in a customary form ofa compression mold so that the following series of layers results:

1st layer: main layer, material A2^(nd) layer: intermediate layer, material AB13^(rd) layer: intermediate layer, material AB24^(th) 4 layer: main layer, material B5^(th) layer: intermediate layer, material BC16^(th) layer: intermediate layer, material BC27^(th) layer: main layer, material C8^(th) layer: intermediate layer, material CD19^(th) layer: intermediate layer, material CD210^(th) layer: main layer, material D

After filling the compression mold with the individual layers the greenbody is produced in known manner by dry pressing, and then processableshaped body with an overall height of approximately 10 to 15 mm isproduced by debindering and sintering. This shaped body may optionallybe subjected to further processing.

In the thus-obtained shaped body the intermediate layers have a layerthickness of approximately 0.2 to approximately 0.4 mm. With this shapedbody and with a dental restoration produced from it, the changes betweenthe individual layers are surprisingly imperceptible to the naked eye.

Example 3 One Intermediate Layer

For the manufacture of a multi-colored shaped body having differentlycolored layers, the following materials (glass ceramic powders) areused:

SiO₂: 60.0-65.0%

Al₂O₃: 16.0-20.0%

K₂O: 10.0-14.0%

Na₂O: 3.5-6.5%

B₂O₃: 0-1.0%

BaO: 0-1.5%

CaO: 0.5-2.5%

CeO₂: 0-1.0%

TiO₂: 0-0.5%

F: 0-0.5%

Pigments: 0.2-1.0%

By appropriate pigment addition, the colorings M1 and M2 of the glassceramic material are produced, wherein M1 for example corresponds to thedentine color A2 according to Vitapan Classical® and has a high opacity.M2 corresponds to an incisor color and has a lower opacity. By differentmixing of the materials M1 and M2 four differently colored materialcompositions A to D result, and from these in turn three differentlycolored materials of the intermediate layers AB, BC, CD:

Material A: 100% M1

Material B: ⅔ M1, ⅓ M2Material C: ⅓ M1. ⅔ M2

Material D: 100% M2 Material AB: 50% A, 50% B Material BC: 50% B, 50% CMaterial CD: 50% C, 50% D

The individual materials are introduced gradually in a customary form ofa compression mold so that the following series of layers results:

a compression mold so that the following series of layers results:1^(st) layer: main layer, material A2^(nd) layer: intermediate layer, material AB3^(rd) layer: main layer, material B4^(th) layer: intermediate layer, material BC5^(th) layer: main layer, material C6^(th) layer: intermediate layer, material CD7^(th) layer: main layer, material D

After filling the compression mold with the individual layers the greenbody is produced in known manner by dry pressing, and then a processableshaped body with an overall height of approximately 10 to 15 mm isproduced by debindering and sintering. This shaped body may optionallybe subjected to further processing.

In the thus-obtained shaped body the intermediate layers have a layerthickness of approximately 0.2 to approximately 0.4 mm. With this shapedbody and with a dental restoration produced from it, the changes betweenthe individual layers are surprisingly imperceptible to the naked eye.

All numbers expressing quantities or parameters used in thespecification are to be understood as additionally being modified in allinstances by the term “about”. Notwithstanding that the numerical rangesand parameters set forth, the broad scope of the subject matterpresented herein are approximations, the numerical values set forth areindicated as precisely as possible. For example, any numerical value mayinherently contains certain errors, evidenced by the standard deviationassociated with their respective measurement techniques, or round-offerrors and inaccuracies.

Although the present invention has been described in connection withpreferred embodiments thereof, it will be appreciated by those skilledin the art that additions, deletions, modifications, and substitutionsnot specifically described may be made without department from thespirit and scope of the invention as defined in the appended claims.

1. A process for the manufacture of a dental restoration, comprising (i)providing a multi-colored shaped body comprising: at least twosuccessive and differently colored main layers; and at least twodifferently colored intermediate layers between the at least twosuccessive and differently colored main layers; wherein a change incolor between the intermediate layers takes place in a direction whichis contrary to the direction of the change in color between the mainlayers; and (ii) processing the shaped body by means of a computer-aidedtechnique to obtain the dental restoration.
 2. The process according toclaim 1, wherein the change in colors is essentially a change in theirrespective brightness.
 3. The process according to claim 2, wherein anincrease in brightness between the intermediate layers takes place in adirection which is contrary to the direction of the increase inbrightness between the main layers.
 4. The process according to claim 1,wherein the intermediate layers lying between two successive anddifferently colored main layers alternately have the colors of the mainlayers.
 5. The process according to claim 1, wherein between twosuccessive and differently colored main layers two intermediate layersare arranged and each of these intermediate layers has the color of themain layer which is adjacent to the respective other intermediate layer.6. The process according to claim 1, wherein the shaped body comprisesat least one element of four layers arranged on top of one another,wherein (a) the first layer is a first main layer; (b) the second layeris an intermediate layer having the color of a second main layer; (c)the third layer is an intermediate layer having the color of the firstmain layer; (d) the fourth layer is the second main layer.
 7. Theprocess according to claim 1, wherein the shaped body comprises 4-20main and intermediate layers.
 8. The process according to claim 7,wherein the shaped body comprises 4-10 main and intermediate layers. 9.The process according to claim 8, wherein the shaped body comprises 4-8main and intermediate layers.
 10. The process according to claim 1,wherein the shaped body has eight layers arranged on top of one another,wherein (a) the first layer is a first main layer; (b) the second layeris a second main layer; (c) the third layer is an intermediate layerhaving the color of a third main layer; (d) the fourth layer is anintermediate layer having the color of the second main layer; (e) thefifth layer is the third main layer; (f) the sixth layer is anintermediate layer having the color of a fourth main layer; (g) theseventh layer is an intermediate layer having the color of the thirdmain layer; and (h) the eighth layer is the fourth main layer.
 11. Theprocess according to claim 1, wherein the main layers have a thicknessof more than about 0.5 mm.
 12. The process according to claim 11,wherein the main layers have a thickness of about 0.5 mm-15 mm.
 13. Theprocess according to claim 12, wherein the main layers have a thicknessof about 0.5 mm-10 mm.
 14. The process according to claim 13, whereinthe main layers have a thickness of about 0.7 mm-8 mm.
 15. The processaccording to claim 1, wherein the intermediate layers have a thicknessof up to about 0.5 mm.
 16. The process according to claim 15, whereinthe intermediate layers have a thickness of about 0.01 mm-0.5 mm. 17.The process according to claim 16, wherein the intermediate layers havea thickness of about 0.1 mm-0.5 mm.
 18. The process according to claim17, wherein the intermediate layers have a thickness of about 0.2 mm-0.4mm.
 19. The process according to claim 1, wherein the shaped body isformed from ceramic, glass ceramic, inorganic-organic composite, plasticor mixtures thereof.
 20. The process according to claim 1, wherein theshaped body is formed from: (a) SiO₂; (b) Al₂O₃; and (c) K₂O and/orNa₂O.
 21. The process according to claim 1, wherein the shaped body isformed from an Al₂O₃ and/or ZrO₂ ceramic material.
 22. The processaccording to claim 1, comprising processing the shaped body by means ofa CAD/CAM technique.
 23. The process according to claim 1, wherein thedental restoration comprises artificial teeth, inlays, onlays, bridgesor crowns.
 24. A dental restoration manufactured by the processaccording to claim
 1. 25. A process for the manufacture of a dentalrestoration, comprising: (i) providing a multi-colored shaped bodycomprising: at least two successive and differently colored main layers;and an intermediate layer between at least two successive anddifferently colored main layers; wherein the intermediate layercomprises a mixture of the materials of the two successive main layers;and (ii) processing the shaped body by means of a computer-aidedtechnique to obtain the dental restoration.
 26. The process according toclaim 25, wherein the shaped body comprises 4-20 main and intermediatelayers.
 27. The process according to claim 26, wherein the shaped bodycomprises 4-10 main and intermediate layers.
 28. The process accordingto claim 27, wherein the shaped body comprises 4-8 main and intermediatelayers.
 29. The process according to claim 25, wherein the main layershave a thickness of more than about 0.5 mm.
 30. The process according toclaim 29, wherein the main layers have a thickness of about 0.5 mm-15mm.
 31. The process according to claim 30, wherein the main layers havea thickness of about 0.5 mm-10 mm.
 32. The process according to claim31, wherein the main layers have a thickness of about 0.7 mm-8 mm. 33.The process according to claim 25, wherein the intermediate layer has athickness of up to about 0.5 mm.
 34. The process according to claim 33,wherein the intermediate layer has a thickness of about 0.01 mm-0.5 mm.35. The process according to claim 34, wherein the intermediate layerhas a thickness of about 0.1 mm-0.5 mm.
 36. The process according toclaim 35, wherein the intermediate layer has a thickness of about 0.2mm-0.4 mm.
 37. The process according to claim 25, wherein the shapedbody is formed from ceramic, glass ceramic, inorganic-organic composite,plastic or mixtures thereof.
 38. The process according to claim 25,wherein the shaped body is formed from: (a) SiO₂; (b) Al₂O₃; and (c) K₂Oand/or Na₂O.
 39. The process according to claim 25, wherein the shapedbody is formed from an Al₂O₃ and/or ZrO₂ ceramic material.
 40. Theprocess according to claim 25, comprising processing the shaped body bymeans of a CAD/CAM technique.
 41. The process according to claim 25,wherein the dental restoration comprises artificial teeth, inlays,onlays, bridges or crowns.
 42. A dental restoration manufactured by theprocess according to claim 25.